Question

A swimmer wants to cross a river, from point A to point B, as shown
in the figure. The distance(from
A to C) is 200,
the distance(from
C to B) is 150,
and the speedof
the current in the river is 5.
Suppose that the swimmer's velocity relative to thewatermakes
an angle ofwith
the line from A to C, as indicated in the figure.

To swim directly from A to B, what speed, relative to the water, should the swimmer
have?

Express the swimmer's speed numerically, to three significant
figures, in kilometers per hour.